The present invention is directed to a method for manufacturing an optical cable, which has an extruded outside cladding in which are embedded both tensile elements and supporting elements.
U.S. Pat. No. 4,743,085, which is incorporated herein by reference thereto, discloses an optical cable in whose outside cladding both tensile elements as well as supporting elements are embedded. The tensile elements are preferably employed for absorbing corresponding longitudinal forces, for example, when laying the cable or during the operation of the cable, for example given overhead cables. By contrast thereto, the supporting elements are important particularly in view of shrink forces of the cable cladding, for example given great changes in the temperature. For example, the tensile elements can be composed of rovings or can be manufactured in the form of yarns or strings. They are relatively flexible, whereas the supporting elements can be composed, for example, of epoxy-cast glass fibers, which are known as GFK elements (fiberglass-reinforced plastic), or FRP elements (fiber-reinforced plastics). These supporting elements are correspondingly stiff, less easily bent and can hardly be compressed at all in the longitudinal direction. The tensile and supporting elements are present as prefabricated elements and must both be introduced into the extruder head so that they can be embedded into the cladding material. This can usually be relatively easily accomplished given the relative flexibility of the tensile elements, whereas the stiff, rather rod-like supporting elements can lead to difficulties in their handling. Moreover, prefabricated supporting elements are generally significantly more expensive than, for example, coextruded supporting elements.